To achieve high levels of illumination of a particular environment at low cost it is typically desirable to provide high brightness sources with several different mounting locations. Glare is a common problem encountered in lighting installations when the direct visibility of high brightness sources can be visually uncomfortable and may be potentially hazardous.
LED technology can achieve luminous emittance of 108 lux directly at the chip level. Such chips when viewed directly can produce excessive amounts of light for an observer looking at them. For the present description, glare is defined as the intensity of a light source that is seen by an observer from a particular viewing position when looking directly at the light source. To reduce the effect of glare, the light is typically spread over a much larger area (for example in troffers, wall washers and other light baffling arrangements); is directed into a narrow cone angle (by means of light shades or directional optics) so that high glare is only visible from a narrow range of angles; or the mounting position of light sources is typically at high level to avoid line of sight viewing of the source. The glare considerations of human vision limit the maximum source brightness that can usefully be implemented, and place constraints on the useful location of illumination apparatuses within the illuminated environment.
PCT/GB2009/002340 describes a method and apparatus to provide a high resolution collimated output from an array of small LEDs (for example 100×100 microns). Such an arrangement is capable of providing a large number of small size (for example 1 mm diameter optical output aperture) substantially collimated beams that may be individually controllable.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.